Annual reproductive cycle probability density contour plots of Burmese python (Python molurus bivittatus) females (top; n = 933 snakes) and males (bottom; n = 1,123 snakes) in southern Florida, USA. Python sizes (snout-vent length; SVL, cm) are shown across months of the year (scale in Julian days) and separated by observed gonad developmental state (colored density polygons at 25%, 50% ,75%, and 99% data contours) from necropsied individuals collected from 2003 through 2021. Grey shaded vertical band represents purported breeding season (approximately 100 days December into March) when seasonal gonadal recrudescence peaks (see text). The purple shaded vertical band for females represents hypothesized oviposition timing (e.g., initiation of nesting season) based on presence of oviductal eggs in specimens, field observations, and published accounts. Note: sample sizes are low for gravid females due to low encounter rates during nesting.